Method and apparatus for preserving perishable material



P 1959 w. MORRISON 2,901,891

METHOD AND APPARATUS FOR PRESERVING PERISHABLE MATERIAL Sept. 1, 1959 w.L. MORRISON METHOD AND APPARATUS FOR PRESERVING PERISHABLE MATERIALFiled Feb. 9, 1956 FIGZ 2 Sheets-Sheet 2 III I I III]! III INVENTOR.

WILLARD L.MORRISON BY PARKER &CARTER ATTORNEYS United gtates Patent FNIETHOD AND APPARATUS 'FOR PRESERVING PERISHABLE MATERIAL ApplicationFebruary 9, 1956, Serial No. 564,537

'13 Claims. (Cl. 62'60) My invention relates to improvement in method ofand apparatus for preserving by cooling such perishable materials asfoodstuifs and the like and has for one object to provide a productionline method whereby such materials may be rapidly and effectively frozenor substantially reduced in temperature.

' My invention is especially, though not exclusively, applicable to asituation where it is desired to cool already frozen foodstuffs totemperatures far below the normal freezing temperatures, that istotemperatures far belowv zero degrees F.

I' propose to cool the material being treated by direct contact with acold, dry gas in gaseous phase, for example, nitrogen which atatmospheric presure does not enter the liquid phase until a temperaturein the order of 320 F. has been reached.

Nitrogen is a suitable gas for this purpose because it may directlycontact the foodstuffs being treated Without deleterious effect thoughany other gas Which may be cooled down to low temperature withoutliquefaction and can contact foodstutfs and the like without deleteriouseflect may well be used, for example, argon, helium or other gases.

By direct contact, I mean that the gas may be allowed to contactwhatever usual container or Wrapper is pro vided. No special gas-tightor gas resisting metal or other containers being needed to protect thematerial against contact with the gaseous coolant.

I propose to move a sequence of open mouthed insulated shippercontainers through a series of step by step stations. At one station thecontainer may be filled with material to be chilled. At the nextstation, it will be precooled, at each of one or more intermediatestations, the temperature will be further reduced until when the desiredminimum temperature has been reached, the container will be closed forstorage or shipment. The particular mechanism for moving the containerstep by step from station to station form no part of-the presentinvention and are not illustrated.

' Other objects will appear from time to time throughout thespecification and claims.

My invention is illustrated more or less diagrammatically in theaccompanying drawings, wherein Figure 1 is a perspective of theapparatus;

Figure 2 is a section along the line 2--2 of Figure 1.

Like parts are indicated by like characters throughout the specificationand drawings.

A cold gas supply duct is indicated at 1. It discharges through anexpanding nozzle 2 into a gas distribution box 3, open at top andbottom, adapted to be closed at the top by aremovable lid 4 and inregister at bottom with a shipper container 14. A duct 5 joins the box 3'with a similar box 7. A duct 8 joins the box 7 to a similar box 9, anda contracting nozzle 12 discharges gas through a pipe 13 to receiver 10.Each of the boxes 7 and 9 may be closed by a lid 4 just as is box 3 andthat lid will also fit and may be installed to close any of theinsulated shipper Patented Sept. 1, 1959 ice containers 14, when theyare not associated with the gas distribution boxes 3, 7 and 9.

I have illustrated a number of separate stations. The station occupiedby the box 3, I prefer to call the superchill station. The stationoccupied by the box 7 the intermediate station and that occupied by thebox 9 the initial chilling station.

Assuming that a lid 4 closes the upper open face of each of the boxes 3,7 and 9, the four shipper containers associated with those boxes may beraised upwardly by platens 15 supported by plungers 16 actuated byhydraulic cylinders 17 so that each shipper container is brought intocontact with the under open face of its associated gas distribution box.When cold gas is forced into box 3 from pipe 1, it circulates from boxto box to discharge through pipe 13, the gas is warmed as it passes fromshipper container to shipper container, the contents of the shippercontainers being correspondingly chilled.

Each shipper container is supported by the conveyor belts 18 travelingalong rollers 19 which as shown in Figure 1 rotates in a counterclockwise direction and held in position on the belts by cleats 20 sothat as the belt moves forward one step, each shipper container isbrought into register with the platen 15 associated with the nextcooling station. Shipper container 14 may be placed on the belts at thefeed end of the system. It may be filled with material to be chilled asindicated at 21 either before or after it is placed on the belt and thismay be done either manually or mechanically as desired. 14" will, at thedischarge end or" the system, be closed prior to removal by one of thelids or covers 4.

When the shipper container 14 has moved forward into register with thebox 9, the cover 4 is placed on the box and the shipper containerbrought into engagement with the underside of the box, the gas precoolsthe contents of the shipper container and also the under surface of thecover. When the shipper container is moved into register with the box 7,the cover is moved forward in register with the box 7, the same thinghappens when the shipper container register with the box 3 andthereafter the container is discharged in proper cooled condition havingpassed through the various cooling stations. The cover which hastraveled with each container and which has been chilled accordingly willbe placed on the shipper container which is then closed for storage andshipment.

The gas which picked up heat as it travels from stage to stage in boxes3, 7 and 9 but still, of course, is quite being circulated as a coolantand will be so small in quan-' cold gas, is discharged from receiver 10to enter a gas to gas heat exchanger 22. The pipe 23 conducts the gas toa first stage compressor 24 where it is compressed and raised intemperature. The gas passes through the duct 25 to a water cooler 26which extracts the heat of compression. The gas then goes through theduct 27 to the second stage compressor 28 where it is compressed andwarmed and discharged to a Water cooler 30, thence through a duct 31 tothe gas to gas heat exchanger 22 where the gas at higher pressure, theheat of compression having been extracted by the water coolers isfurther cooled so that when it is discharged through the pipe 32 fromthe heat exchanger 22, it may expand and do work in the expander 33 fordischarge as cold gas through the pipe 1 back to the cooling heads orboxes.

A motor 34 furnishes the additional power needed to operate the system.Water connections 35, 36 provide cold Water circulation through theWater coolers 26 and 30.

As each successive shipper container filled with the food or othermaterial to be chilled comes in register with the prechilling gasdistribution box or cooling head, it will contain some air. That airwill be in very small quantity in proportion to the volume or weight ofthe gas tity that it can be disregarded even though there may result aslight dilution of the coolant gas. Each time a new container is addedto the system, this happens and finally after the dilution has reached adangerous point, the nitrogen may be discharged and a new supply willreplace it.

The circulation of the gas will take place only during the time that theshipper containers are in the raised position, brought snugly up againstthe under side of the gas distribution boxes. Before the shippercontainers are lowered to the belt for movement to the next step,circulation will be stopped by turning off the power on the motor 34 andcirculation will start again when the system is again closed.

The gas used for refrigeration according to my invention is very muchcolder than the ambient air in the shipper container and at each stationis very much colder than the gas or air contained within the shippercontainer. Such cold gas always rapidly seeks a lower level, expellingthe lighter warmer gas. Packages of foodstuff and the like are alwaysmore or less irregular in shape. They are frequently of wood or fiberboard and they cannot be packed together tightly. Thus there is alwayssubstantial clearance between and about the packages through which suchcold gas may sink as it tends to expel the warmer gas. Th-us step bystep the gas is warmed and the contents of the shipper containers ischilled until at the end of the cycle the contents of the shippercontainer at the superchill station has reached the low point desiredfor shipment.

A receiver 10, preferably of variable capacity is in the line betweenthe final pre-cooled box 9 and the gas to gas heat exchanger 22 topermit expansion and contraction of the gaseous volume of the systemdepending upon change in temperature and depending upon whether or notthe motor 34 is operating. Suitable control valves not here illustrated,since they form no part of the present system may be used in consonancewith the stopping and starting of the motor. The electric controls forstopping and starting the motor 34 forming no part of the presentinvention are also not here illustrated.

I claim:

1. Means for chilling foodstuffs and the like comprising a plurality ofinsulated shipper containers, means for moving them in unison step bystep from a precooling to a superchilling station, a separate gasdistribution box at each station in register and in communication withthe container at such station, means for circulating cold gas throughsaid boxes in series in a direction opposite to the step by stepmovement of the shipper container, means for discharging the warmed gasfrom the last of said boxes, recooling it and supplying it to the firstof said boxes in the series, means for connecting the boxes in series,said means conducting all the gas from one box into the next in theseries.

2. Means for chilling foodstuffs and the like comprising a plurality ofinsulated shipper containers, means for moving them in unison step bystep from a precooling to a superchilling station, a separate gasdistribution box at each station in register and in communication withthe container at such station, means for circulating cold gas throughsaid boxes in series in a direction opposite to the step by stepmovement of the shipper container, means for discharging the warmed gasfrom the last of said boxes, recooling it and supplying it to the firstof said boxes in the series, means for connecting the boxes in series,said means conducting all the gas from one box into the next in theseries, conveying means adapted to support the shipper containers, meansassociated with each station for lifting the shipper at.

such station from the conveying means and holding it in register withthe box at such station.

3. Means for chilling foodstufis and the like comprising a conveyor, aplurality of insulated shipper conadapted to be supported on and carriedby said.

conveyor, means for positively positioning each shipper container inspaced longitudinal relationship with the others on the conveyor, aplurality of separate gas dis tribution boxes spaced along the conveyorand defining a plurality of cooling stations, means at each station forelevating each shipper container from the conveyor and holding it inregister with and in communication with the box at that station, meansfor circulating cold gas through said boxes and the shipper containersin series at the successive stations.

4. Means for chilling foodstuffs and the like comprising a conveyor, aplurality of insulated shipper containers adapted to be supported on andcarried by said conveyor, means for positively positioning each shippercontainer in spaced longitudinal relationship with the others on theconveyor, a plurality of separate gas distribution boxes spaced alongthe conveyor and defining a plurality of cooling stations, means at eachstation for elevating each shipper container from the conveyor andholding it in register and in communication with the box at thatstation, means for circulating cold gas through said boxes and theshipper containers in series at the successive stations, a cover foreach shipper container, the cover being adapted to register with andclose the shipper container after it has left the last station and toclose and be cooled by the gas circulating through the box associatedwith each of the shipper containers.

5. Means for chilling foodstuffs and the like com-. prising a pluralityof insulated shipper containers, a plurality of cooling stations, meansfor placing each shipper container step by step in register with each ofthe cooling stations, means for circulating cold gas through each of thecooling stations in sequence whereby the contents of the containers arestep by step cooled, there being a removable cover for each of theinsulated shipper containers, the covers being adapted to be placed inregister with the successive cooling stations as the associated shippercontainer moves step by step into register with each of the coolingstations whereby the cover associated with each shipper container iscooled in consonance with the cooling of the contents of the shippercontainer, each cooling station including a frame adapted to registerwith the shipper container and rest thereupon, open at the bottom inregister with the shipper container, a cover associated with eachshipper container adapted to be. placed on and close the top of the boxwhereby the. covers are cooled by the cold air entering the shippercontainer.

6. Means for chilling foodstuifs and the like com-. prising a pluralityof insulated shipper containers arranged in sequence and each open atthe top, a gas distribution box open to and in register with and closingthe. open top of each shipper container, means for supplying cold gas tothe first distribution box in the sequence, means for conducting gasfrom each distribution box to the next in the sequence, means forwithdrawing the gas from the last box in the sequence.

7. Means for chilling foodstuffs and the like comprising a plurality ofinsulated shipper containers arranged in sequence and each open at thetop, a gas distribution box open to and in register with and closing theopen top of each shipper container, means for supplying cold gas to thefirst distribution box in the sequence, means for conducting gas fromeach distribution box to the next in the sequence, means for withdrawingthe gas from the last box in the sequence, means for recooling' the gasand returning it to the first distribution box in the sequence.

8. Means for chilling foodstuffs and the like comprising a plurality ofinsulated shipper containers ar-t ranged in sequence and each open atthe top, a gas distribution hox open to and in register with and closingthe open top of each shipper container, means for supplying cold gas tothe first distribution box in the sequence, means for conducting gasfrom each distribution box to? the next in the sequence, means forwithdrawing the gas;

from the last box in the sequence, each of the distribution boxes beingopen at the bottom in register with its associated shipper container andopen at the top, there being covers for each shipper container, thecovers being adapted to close the open top of the distribution boxwhereby the gas passing through the distribution box into and out of theshipper container simultaneously cools the cover associated with eachrespective shipper container.

9. Means for chilling foodstuffs and the like comprising a plurality ofgas distribution receptacles, a compressor expander, gas chillingapparatus arranged in series with the gas distribution receptacles,means for propelling step by step into register with successive gaschilling receptacles a plurality of open topped shipper containers,means for successively presenting said containers to the gasdistribution boxes in series whereby the cold gas is supplied to thefirst box, passes from it to the other boxes in series and is Withdrawnfor recompression, expansion and cooling, each cooling st-ationincluding a frame adapted to register with the shipper container andrest thereupon, open at the bottom in register with the shippercontainer, a cover associated with each shipper container adapted to beplaced on and close the top of the box whereby the covers are cooled bythe cold air entering the shipper container.

10. Means for chilling foodstuffs and the like comprising a plurality ofgas distribution boxes open at bottom arranged in sequence, means forsupplying cold gas to the first box in the sequence, means forconducting gas from each box to the next in the sequence and means fordischarging gas from the last box of the sequence, a plurality ofinsulated shipper containers open at the top, means for successivelyplacing each of the shipper containers in register with the open bottomof a gas distribution box whereby gas from the box may flow by gravityinto and fill such shipper container, each cooling station including aframe adapted to register with the shipper container and rest thereupon,open at the bottom in register with the shipper container, a coverassociated with each shipper container adapted to be placed on and closethe top of the box whereby the covers are cooled by the cold airentering the shipper container.

11. Means for chilling foodstuffs and the like comprising a plurality ofgas distribution boxes open at the bottom arranged in sequence, meansfor supplying cold gas to the first box in the sequence, means forconducting gas from each box to the next in the sequence and means fordischarging gas from the last box of the sequence, a plurality ofinsulated shipper containers open at the top, means for successivelyplacing each of the shipper containers in register with the open bottomof a gas distribution box whereby gas from the box may flow by gravityinto and fill such shipper container, the open bottom of thedistribution box being substantially coextensive with and insubstantially gas-tight contact with the open top of the shippercontainer, each cooling station including a frame adapted to registerwith the shipper container and rest thereupon, open at the bottom inregister with the shipper container, a cover associated with eachshipper container adapted to be placed on and close the top of the boxwhereby the covers are cooled by the cold air entering the shippercontainer.

12. Means for chilling foodstufis and the like comprising a plurality ofgas distribution boxes open at top and bottom arranged in sequence,means for supplying cold gas to the first box in the sequence, means forconducting gas from each box to the next in the sequence and means fordischarging gas from the last box of the sequence, a plurality ofinsulated shipper containers open at the top, means for successivelyplacing each of the shipper containers in register with the open bottomof a gas distribution box whereby gas from the box may flow by gravityinto and fill such shipper container, there being a plurality of shippercontainer covers each adapted to close the open top of a gasdistribution box, each cooling station including a frame adapted toregister with the shipper container and rest thereupon, open at thebottom in register with the shipper container, a cover associated witheach shipper container adapted to be placed on and close the top of thebox whereby the covers are cooled by the cold air entering the shippercontainer.

13. Means for chilling foodstuffs and the like comprising a plurality ofgas distribution boxes open at top and bottom arranged in sequence,means for supplying cold gas to the first box in the sequence, means forconducting gas from each box to the next in the sequence and means fordischarging gas from the last box of the sequence, a plurality ofinsulate-d shipper containers open at the top, means for successivelyplacing each of the shipper containers in register with the open bottomof a gas distribution box whereby gas from the box may floW by gravityinto and fill such shipper container, there being a plurality of shippercontainer covers each adapted to close the open top of a gasdistribution box, the open bottom of the distribution box beingsubstantially coextensive with and in substantially gas-tight contactwith the open top of the shipper container, each cooling stationincluding a frame adapted to register with the shipper container andrest thereupon, open at the bottom in register with the shippercontainer, a cover associated with each shipper container adapted to beplaced on and close the top of the box whereby the covers are cooled bythe cold air entering the shipper container.

References Cited in the file of this patent UNITED STATES PATENTS1,994,233 Shaw Mar. 12, 1935 2,077,608 Wood Apr. 20, 1937 2,237,257Finnegan Apr. 1, 1941 2,527,542 Gilson Oct. 31, 1950

